This is BS... if the system requires a re-calibration after simply replacing the battery, then the re-calibration utility should be BUILT IN TO THE CAR. It has an on-board computer for chrissakes. It would be no thing to add a calibration menu to the iDrive. Heck, if it's already measuring so many params from the battery then it sould be able to SELF DETECT a battery swap and adjust accordingly. It is just plain silliness to have to make a dealer trip for such a simple operation...

BINGO!!!!
BMW has built a Rube Goldberg machine. http://en.wikipedia.org/wiki/Rube_Goldberg
Changing a battery in a car is one of the simplest maintenance tasts that one can do; only slightly more complex than refilling the windshield washer fluid. I like to do the minor maintenance items myself - change oil, change air filters, change the battery, etc. Quite frankly, after reading this thread, I fell less comfortable doing any type of maintenance to the car due to unintended consequences.
This is the final nail in the coffin for me; I'll likely sell my car when the license plates are due for renewal next year and either go with a Cayman S or 911 (yes, Porsches are huge maintenance beasts, but I know that going into the purchase). My wife was going to get a BMW as her next car; after seeing the hassle that I've been going through to get BMW to warranty replace my battery (I will have to sue BMWNA in small claims court), she is now sold forever on Acura.
In my humble opinion, BMW is destroying their brand name. It's too bad; it's a nice driving car once you get rid of the run flats.